The present invention relates to a method of and apparatus for producing a sprayed film of coating sharply defined in contour.
When spray coating is used to produce a pattern or area of a color over or adjacent to another surface pre-coated in different color, as when coating automobile bodies, that edge of the pre-coated surface is also exposed to paint particles currently sprayed so that the outline of the newly coated area occurs other than sharply defined. To obviate this, in conventional spray coating jobs, the adjacent precoated surface which should not be sprayed is covered with masking tape along a sufficiently wide area bordering to its bounding line or entirely to prevent it from being smeared with the sprayed paint particles. After coating, these masking tapes are removed. However, those conventional methods are rather inefficient and not suitable for conveyor production line coating. In addition, those parts of the paint which are deposited on the masking tape entail an utter waste. Moreover, the removal of masking tape results in different problems depending on the time when it is removed. For example, when the coated film is dried, removal causes it to crack, leaving a jagged line along the bounding line. When the film is half-dried, those undried parts of paint which might not entirely adhere to the currently sprayed area can also be peeled off with the tape being removed, with the boundary having a resultant jagged outline.